The sun activates all renewable energy systems on Earth. Water, wind, and sun power sourcing starts with the sun! However, comparing these renewable energy schemes shows how sourcing and producing solar power requires the least resources.
Water Power Challenges
Water-based renewable energy schemes generate and distribute electricity derived from falling water or any other form of moving water. (1)
When solar radiation interacts with water, water vapor forms as a result of convection. Convection is “the transfer of heat by the circulation or movement of the heated parts of a liquid or gas,” in this case water and water vapor. (1) This water vapor initiates the hydrologic cycle that transports water to land.
Energy can be extracted from water moving on land by using hydroelectric devices. (6)
For water energy to produce electricity, however, a difference in height and energy extraction point is needed. Without a river or waterfall, additional resources are required to prepare and control water motion. (5) Primary water energy extractors include dams and low head hydroelectrics.
Wind Power Challenges
Wind-based renewable energy schemes exploit wind to produce energy. (4)
When solar radiation interacts with the Earth’s surface, a temperature gradient results between the equator and the poles in the form of wind as a moving medium. “Wind forms when the sun heats one part of the atmosphere differently than another part. This causes expansion of warmer air, making less pressure where it is warm than where it is cooler. Air always moves from high pressure to lower pressure, and this movement of air is wind.” (2)
Energy can be extracted from this wind by using wind turbines. (4)
For wind energy to produce electricity, however, a smooth wind source is needed. Regardless of ideal turbine placement in an area free of trees and buildings, numerous resources are required to capture wind motion. (4) Primary wind extractors include windmills and wind turbine towers.
The Importance of Sun Power
Sun-based renewable energy schemes absorb solar radiation as a direct way to convert sunlight into electricity. (1)
When solar radiation interacts with the Earth’s atmosphere, it produces light energy. We receive this light energy either as a direct line emission from the sun or as an indirect line emission bouncing around molecules and gases in the air. (3)
The Earth absorbs sun rays across the entirety of the solar spectrum from many directions. In other words, any solar radiation can be extracted from both direct and indirect emission types. (1)
For solar energy to produce electricity, sunlight is needed. Primary solar energy extractors include solar power towers, as well as solar panels containing solar cells.
Renewable energy generally depends on sun ray absorption relative to location on the planet. Thus water, wind, and solar energy infrastructures affect cost. All three types rely on motion as free of resistance as possible. Of the three renewable power sources, solar power generates electricity of least resistance and therefore least cost.
As we deplete finite, nonrenewable fossil fuel resources, harnessing solar radiation can fill energy demand gaps. Solar energy also produces almost no pollutants. (5) For these reasons, sun power may be the most important renewable energy source for the future development and well-being of all life on Earth.
2 Lehigh University
3 Oberlin College and Conservatory
4 Open Energy Information
5 United States Energy Information Administration